The invention relates to managing calls over a data network, such as an Internet Protocol (IP) network.
Packet-based data networks are widely used to link various nodes, such as personal computers, servers, gateways, and so forth. Packet-based data networks include private networks, such as local area networks (LANs) and wide area networks (WANs), and public networks, such as the Internet. The increased availability of such data networks has increased accessibility among nodes, whether the nodes are located in close proximity to each other (such as within an organization) or at far distances from each other. Popular forms of communications across such data networks include electronic mail, file transfer, web browsing, and other exchanges of digital data.
With the increased capacity and reliability of data networks, voice communications over data networks, including private and public networks, have become possible. Voice communications over packet-based data networks are unlike voice communications in a conventional public switched telephone network (PSTN), which provides users with dedicated, end-to-end circuit connections for the duration of each call. Communications over data networks, such as IP (Internet Protocol) networks, are performed using packets that are sent in bursts from a source to one or more destination nodes. Voice data sent over a data network has to share the network bandwidth with conventional non-voice data (e.g., electronic mail, file transfer, web access, and other traffic). One standard that has been implemented for communications of voice as well as other data is the H.323 recommendation from the Telecommunication Sector of the International Telecommunication Union (ITU-T), which describes terminals, equipment and services for multimedia communications over packet-based networks.
In an IP data network, each data packet is routed to a node having destination IP address contained within the header of each packet. Data packets may be routed over separate network paths before arriving at the final destination for reassembly. Transmission speeds of the various packets may vary widely depending on the usage of data networks over which the data packets are transferred. During peak usage of data networks, delays added to the transfer of voice data packets may cause poor performance of voice communications. Voice data packets that are lost or delayed due to inadequate or unavailable capacity of data networks or resources of data networks may result in gaps, silence, and clipping of audio at the receiving end.
A need thus exists for an improved method and system to manage the quality of voice calls or other audio communications over data networks.
In general, according to one embodiment, a method of managing calls over a data network includes determining usage information of the data network. A call request is received for establishing a call between at least two network terminals. One or more of a plurality of resource elements are selected as candidates for use in the requested call in response to the call request based on usage information of the data network.
In general, according to another embodiment, a method of managing calls in a telephony system includes defining a plurality of communities each including one or more communication endpoints and assigning one or more usage threshold values to a link between communities. Further, a call request is processed based on the one or more usage threshold values. The processing includes determining whether to admit the call request over the link.
Some embodiments of the invention may provide one or more of the following advantages. Resource elements can be selected to optimize quality of service while at the same time taking into account the usage of the data network as well as usage of other transmission or communications resources. Proper selection of resource elements as well as call admission control reduces the likelihood of overburdening links between terminals. As a result, the likelihood of delays in the communication of audio data that may lead to various audio distortions is also reduced. By efficiently using packet-based data networks for telephony and other forms of audio communications, sharing of such data networks for carrying audio data (which are relatively time sensitive) and traditional forms of digital data (such as electronic mail traffic, file transfer traffic, and other traffic) can be made more effective.
Other features and advantages will become apparent from the following description and from the claims.